U.S. patent application number 14/874947 was filed with the patent office on 2016-05-05 for high performance moldable composite.
The applicant listed for this patent is Nonwoven Networks LLC. Invention is credited to Stephen W. Foss, Jean-Marie Turra.
Application Number | 20160121814 14/874947 |
Document ID | / |
Family ID | 54557228 |
Filed Date | 2016-05-05 |
United States Patent
Application |
20160121814 |
Kind Code |
A1 |
Foss; Stephen W. ; et
al. |
May 5, 2016 |
HIGH PERFORMANCE MOLDABLE COMPOSITE
Abstract
A moldable composite with high heat resistance and noise
absorption properties utilizes nonwoven fabrics and a heat
resistance additive. The composition that provides both superior
acoustic performance and excellent flex modulus that may be
utilized in automotive products and applications in interior and
exterior structures. A blowing agent may be utilized to create
micro porous cells in a polymer non-woven structure. The cells or
voids make the material lighter and allow the material to have
superior acoustic properties that are useful in automotive
applications.
Inventors: |
Foss; Stephen W.; (Naples,
FL) ; Turra; Jean-Marie; (Greer, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nonwoven Networks LLC |
Naples |
FL |
US |
|
|
Family ID: |
54557228 |
Appl. No.: |
14/874947 |
Filed: |
October 5, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62185575 |
Jun 27, 2015 |
|
|
|
62072305 |
Oct 29, 2014 |
|
|
|
Current U.S.
Class: |
181/290 ;
156/244.11; 264/45.3 |
Current CPC
Class: |
B32B 5/022 20130101;
B29K 2105/25 20130101; B29C 48/0018 20190201; B29L 2031/3005
20130101; B29K 2105/041 20130101; B29K 2105/045 20130101; B32B
2262/14 20130101; B29C 48/08 20190201; B32B 2605/08 20130101; B32B
2266/025 20130101; B32B 2307/102 20130101; B60R 13/0815 20130101;
D04H 1/558 20130101; D04H 1/541 20130101; B29C 48/0021 20190201;
B29C 66/4722 20130101; B29K 2995/0016 20130101; B32B 5/245
20130101; B29K 2995/0001 20130101; B29K 2067/003 20130101; B32B
37/203 20130101; B29K 2105/04 20130101; B32B 5/20 20130101; D04H
1/435 20130101; B32B 2262/0253 20130101; B32B 2262/0284
20130101 |
International
Class: |
B60R 13/08 20060101
B60R013/08; B29C 65/00 20060101 B29C065/00; B32B 5/20 20060101
B32B005/20; B29C 47/00 20060101 B29C047/00; B32B 5/24 20060101
B32B005/24; B32B 5/02 20060101 B32B005/02 |
Claims
1. A formable automotive structural non-woven composite consisting
of: a blend of fibers, the fibers having a plurality of high melt
fibers and a plurality of low melt fibers to form a first nonwoven
composite layer; the blend of fibers further including a carrier
fiber made of polyethylene glycol (PETG), the PETG fiber is a
non-flame retardant fiber containing an internal flame retardant
selected from the group consisting of polyphosphonates,
organophosphates, phosphonates, antimony trioxide and any
combination thereof; the blend of fibers further having a physical
properties including a flexural modulus sufficient for automotive
structural use, and heat resistance to withstand automotive engine
compartment conditions; the first nonwoven composite layer having
improved acoustic impedance due to decreased nonwoven web pore
sizes created by the low melt fibers when amorphous portions of the
PETG are melted during bonding; and and wherein the formable
composite is used as an automotive structural component for use in
areas around the engine compartment or under the vehicle.
2. The formable composite of claim 1 further including a blown film
layer attached to the first nonwoven composition layer to form a
multi-layer nonwoven composite, the blown film layer having
controlled micro-porosity of the film for restricting air flow and
furthering acoustic impedance properties.
3. The formable composite of claim 2 further including a second
nonwoven composite layer formed from the blend of fibers, the
fibers having a plurality of high melt fibers and a plurality of
low melt fibers, and the second layer attached to the blown film
layer to form a tri-laminate.
4. The formable composite of claim 1 wherein material for the
fibers is selected from the group consisting of polyester, nylon,
acrylic, polypropylene, Polylactic acid, fiberglass and any
combination thereof.
5. The formable composite in claim 1, wherein the low melt fiber is
polyethylene glycol (PETG) cyclohexanedimethanol (CHDM) modified
polyester with or without flame retardants.
6. The formable composite of claim 1 wherein the fibers are from
0.9 to 50 deniers.
7. The formable composite of claim 1 wherein the fibers are from 25
mm (1'') to 180 MM (7.1'') in length.
8. The formable composite of claim 1, wherein the fibers are both
high melt temperature fibers and low melt temperature fibers, and
wherein the low melt and high melt temperature fibers are selected
from a group consisting of polyethylene, low density polyethylene
(LDPE), linear low density polyethylene (LLDPE), high density
polyethylene (HDPE), polypropylene (PP), polyvinylchloride (PVC),
polyethylene terephthalate (PET), polyethylene terephalate
glycol-modified (PETG), polyamide (Nylon), Ethylene Vinyl Acetate,
Isophthalic modified PET, and any combination thereof.
9. The formable composite of claim 8 wherein the high melt
temperature fibers range from 30 to 95% by weight in content.
10. The formable composite of claim 8 wherein the low melt
temperature fibers range from 5 to 70% by weight in content.
11. The formable composite of claim 8 wherein the fibers range from
0.7 to 100 denier and a length from 12 mm to 180 mm (0.5 to
7'').
12. The formable composite of claim 2 further includes a second a
blown film layer combined with the first composite layer or a
second blown film combined with the first composite layer and a
second composite layer.
13. The formable composite of claim 2 wherein the blown film is
defining holes formed using an inert gas during an extrusion
process.
14. The formable composite of claim 13 furthering including use of
an inert gas is selected from a group consisting of air, nitrogen,
carbon dioxide, carbon monoxide, helium, argon, oxygen, and any
combination thereof.
15. The formable composite of claim 14 wherein the holes in the
blown film are formed using a blowing agent blended with the film
at a weight percentage of 0.2% to 3.0%.
16. The formable composite of claim 2 wherein the holes in the
blown film are formed using a blowing agent blended with the film
at a weight percentage of 0.2% to 3.0%.
17. The formable composite of claim 1 wherein the nonwoven fabric
layer is 50 grams per square meter (gsm) to 2000 grams per square
meter (gsm).
18. The formable composite of claim 1 wherein the nonwoven fabric
layer is 50 grams per square meter (gsm) to 1,200 grams per square
meter (gsm).
19. The formable composite of claim 1 wherein the porosity of air
flow measures greater than 1.5 M-RAYLS.
20. A formable composite of claim 1 wherein the low melt PETG fiber
with or without flame retardants is blended with natural fibers
such as cotton, wool, flax, jute, or mineral fibers.
21. A formable composite in claim 1 wherein the PETG fiber with or
without flame retardants is between 5% and 75% of the
composite.
22. The formable composite of claim 21 wherein the flame resistance
rate is V-0.
23. A method of making a formable automotive structural non-woven
composite, comprising: extruding a high melt and a low melt
nonwoven polymeric fibers and incorporating a flame resistant
additive into the low melt fiber having at least one region
defining holes to create a microporous open cell structure for
acoustic impedance, and heat and flame resistance.
24. The method of claim 23 wherein the flame resistant additive is
a polyphosphonate.
25. The method of claim 24 wherein the extruding is done below
290.degree. C. to avoid degradation of the polyphosphonate.
26. A method of making a formable automotive structural non-woven
composite, comprising: compounding a flame retardant into a carrier
fiber, wherein the flame retardant is supportive to provide heat
resistance to withstand automotive engine compartment conditions
and the flame retardant is selected from a group consisting of
polyphosphonate, organophosphates, phosphonates, antimony trioxide,
halogens and any combination thereof; and wherein the carrier fiber
is selected from a group consisting of polyethylene glycol (PETG)
cyclohexanedimethanol (CHDM), polyester, nylon, acrylic,
polypropylene, polylactic acid, fiberglass, and any combination
thereof; said compounding done below 290.degree. C. with no heat
history; drawing the carrier fiber at a low draw ratio of
approximately 2-2.5 to prevent crystallinity from occurring thereby
creating an amorphous carrier fiber; and creating a nonwoven web
material having pores by combining the carrier fiber with a blend
of fibers having physical properties that includes a flexural
modulus sufficient for automotive structural use, wherein amorphous
fibers will melt at a lower temperature filling the pores within
the nonwoven material to block air and create resistance for
sound.
27. The method of making a formable automotive structural non-woven
composite of claim 26, further comprising: combining a first layer
nonwoven material having improved acoustic impedance due to
decreased nonwoven web pore sizes with a blown film layer to form a
multi-layer nonwoven composite, the blown film having controlled
micro-porosity of the film for restricting air flow and furthering
acoustic impedance properties.
28. The method of making a formable automotive structural non-woven
composite of claim 27, further comprising: combining a second layer
nonwoven material to the blown film layer, and forming a tri-layer
composite material that has acoustic impedance properties, moisture
resistance, structural integrity, and heat resistance to withstand
environmental conditions inside an automobile engine compartment
and underneath the automobile's undercarriage and wheel wells.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims the benefit of the filing
date of U.S. Provisional Patent Application No. 62/072,305 filed
Oct. 29, 2014 and U.S. Provisional Patent Application No.
62/185,575 filed Jun. 27, 2015, the disclosures of which are hereby
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The need for higher performance materials in the automotive
industry has increased more than ever in past decades Improved
technology has produced cars that not only drive faster and more
economical but also have more electronic options such as in
multimedia devices. Once where an auxiliary-in port was rare in an
automobile, today they are fully connected with USB and Bluetooth
ports and the like that integrate media players and cell phones
directly into factory sound systems. With this increase demand on
automobile sound systems, a requirement for better acoustics in the
automobile has been seen in recent years.
[0003] Acoustic impedance is an important physical property in
substances that determine the substances ability to absorb sound.
Specific Acoustic Impedance is the ratio between the sound pressure
and the particle velocity produced by a sound wave moving through
the substance. When sound waves pass through any physical
substance, pressure of the sound waves causes the particles of the
substance to move. Specific Acoustic Impedance is also directly
related to the resistance of airflow. Specific Acoustic Impedance
is measured in RAYLS. The higher number of RAYLS, the lower the
velocity of sound transmission through a medium. A fabric is
considered to have better acoustic sound absorption with a higher
RAYLS number.
[0004] Having external noises removed from the automobile cabin is
an issue that automobiles of the past did not need to contend with,
however, with advancements in digital media and sound systems for
cell phones, music and the like, the importance of filtering out
external sounds from the driver's cabin is more important than ever
before.
[0005] In the past, wind noise was a significant cause of noise in
automobiles. When automobiles were not aerodynamically shaped as
they are now, various objects like chrome molding surrounding the
windshield glass created turbulence resulting in wind noise. Wind
turbulence around door mounted minors was also a notorious noise
maker. However, today's streamlined designs have significantly
reduced such turbulence along with its accompanying noise. However,
even with the aerodynamic design, today's cars still have air
rushing past the vehicle creating noise heard through the
doors.
[0006] Today noise created by the road traveled is one of the
largest contributors to noisy automobile interiors. Road noise
typically originates from tires running over road surfaces and may
take on two forms of noise called acoustic noise and conductive
noise.
[0007] Acoustic noise is transmitted from the surface of the road
through the air and into the driver's cabin. This noise may be
treated by adding acoustical material to surround the driver's
cabin and doors. However such materials lack the structural
properties and strength as well as the light weight needed for
automotive applications.
[0008] Conductive road noise is caused by vibrations conducted from
the road surface through the automobile's tires and suspension into
the driver's cabin. Even with advancements in tire technology to
achieve quieter tires noise is still produced by the road and
enters into the driver's cabin. With today's common use of run flat
tires or low profile tires, these noises are compounded due to the
significant amount of less rubber on the tires of today's
automobiles. Thus there still remains a need for a material that is
structural sound for automotive applications lightweight and
produced the acoustic effect necessary to eliminate noise in the
driver's cabin for today's electronics and sound systems.
[0009] In addition, due to the higher performance automobiles,
generation of heat from the engine has become an ever increasing
problem. Within the Automotive Industry over the past 50 years,
there have been increased requirements for improved flame
resistance. After many car fires, the industry adopted standard
MVSS 302 from the National Highway Traffic Safety administration.
Even with the evolution of all-electric vehicles, there is a need
for improved fire resistant and low-smoke fabrics. This test is a
horizontal burn test that tests among other things the flammability
of the interior of the automobile and engine compart. The test
involves taking a sample 14''.times.4'' and placing the sample on a
metal frame. A flame via a Bunsen burner or other device is applied
under the front edge of the 4'' width. The flame is placed under
the fabric and the fabric is allowed to burn for 15 seconds.
[0010] Originally this flame test required that fabric burn less
than 101.6 mm/minute (4 inches/minute). The presence of any noxious
gases is also observed during the test. Over the years, many
automobile manufacturers have made the flame test results more
restrictive. Some automotive manufacturers have reduced the burn
rate to 2 inches per minute and down to 1 inch per minute. The
requirements for some applications, for example such as engine
compartment areas, have required that the sample be SE
(self-extinguishing) with a zero burn rate and in some cases with
the strictest requirement which is DNI (did not ignite).
[0011] Recently, several Automotive Manufacturers have focused on
another flame test developed by Underwriters Laboratories, a flame
test UL-94, which is a vertical flame test. This flame test
requires a 5''.times.1/2'' fabric sample held vertically. A flame
is placed under the fabric sample for two-10 second intervals.
[0012] The results of the flame test UL-94 are report as: [0013]
HB: slow burning on a horizontal specimen; burning rate <76
mm/min for thickness <3 mm or burning stops before 100 mm [0014]
V-2 burning stops within 30 seconds on a vertical specimen; drips
of flaming particles are allowed. [0015] V-1: burning stops within
30 seconds on a vertical specimen; drips of particles allowed as
long as they are not inflamed. [0016] V-0: burning stops within 10
seconds on a vertical specimen; drips of particles allowed as long
as they are not inflamed. [0017] 5VB: burning stops within 60
seconds on a vertical specimen; no drips allowed; plaque specimens
may develop a hole. [0018] 5VA: burning stops within 60 seconds on
a vertical specimen; no drips allowed; plaque specimens may not
develop a hole.
[0019] The automotive industry, among other industries, have found
it very difficult if not impossible to find fibrous nonwoven
fabrics that can meet both the above acoustic and flame resistance
requirements. Fabrics are needed in the automotive industry for
good acoustical qualities and these fabrics must be located near
the engine or exhaust system so flame resistance properties are
essential. There is also a need for fabrics with low-smoke
properties. Further, there is a need for fabrics that are moldable
with standard thermoplastic molding equipment, yet still have
excellent thermal stability after molding. There still remains in
the art a need for a moldable nonwoven fabric with enhanced flame
resistance and excellent thermal stability.
[0020] Single layer nonwovens have tried to increase RAYLS by using
more fine fibers to create a denser medium to reduce air flow, and
hence reduce sound transmission. However this technique has not
been achieved at a practical cost or weight.
[0021] At the same time, the Automobile Manufacturers have found a
need for an Underbody Shield to be moldable, durable and fit under
the vehicle to prevent road and wind noise from penetrating upward
into the passenger compartment. Further, it has been shown that
these composites are weighing close to 2,000 gsm (grams per square
meter) to achieve the noise reduction levels desired. This amount
of weight is too much for an automobile part due to stability of
the vehicle, drag and energy efficiency concerns.
[0022] In addition, due to the high heat exposure from engine
parts, a need exists for a product that does not exhibit failure
during heat aging up to 150.degree. C.; has resistance to water,
oil, and engine fluids, has low flame spread and low smoke, and is
recyclable back into itself. Further, these moldable products must
have excellent abrasion resistance against sand & gravel.
[0023] Further environmental factors for automotive products
include the exposure to moisture. Any materials coated with heat
resistant coatings or coatings that increase acoustic impedance are
easily worn away by the harsh environmental conditions of the
undercarriage and wheel wells of the automobile. Rain, snow, ice
and salt as well as other particles are common environmental
conditions that affect an automobile's undercarriage and wheel
wells as well as other portions of the automobile. Any coatings or
non-structural material used that contain heat resistant or
acoustical properties are easily worn away in such
environments.
[0024] Thus there still exists a need for an acoustic absorber that
is thermo-formable or otherwise moldable, light weight, resistant
to water penetration and other environmental factors, flame
resistance, and has a high RAYLS number.
SUMMARY OF THE INVENTION
[0025] The invention utilizes a flame resistance additive into a
polymer such as a polyester, including but not limited to PET, PETG
and the like. Such flame resistance additives may include for
example, polyphosphonates, such as found in the Americhem 33558-F1
(CAS #68664-06-2). This flame resistance family of compounds was
found very successful for low smoke and flame spread. Certain
polyphosphonates are used in PET for children's sleepwear and are
considered safe for personnel use and the environment. Other flame
resistant additives such as organophosphates, phosphonates,
antimony trioxide, and the like may also be used. There is a wide
class of organohalogen compounds that are effective but they may
carry safety and health concerns.
[0026] By incorporating a flame resistance additive into a molten
polymer of the high melt fiber, a highly flame resistant moldable
composite can be formed that will meet newer, more stringent flame
resistance. The process is preferable performed where the fiber is
extruded below 300.degree. C. and more preferably below 290.degree.
C.
[0027] The method of manufacturing the nonwoven automotive material
of the present invention requires a carrier fiber that is
compounded to contain a flame retardant. The flame retardant is not
a coating and is instead chemically bonded to the fiber during the
compounding process. The carrier fiber, preferably polyethylene
glycol (PETG) cyclohexanedimethanol (CHDM) or the like is
compounded with a flame retardant. The PETG is a stiff material
giving strong physical properties needed for automotive structural
use unlike other polymers like polyurethane and other Styrofoam
(expanded polystyrene) like materials. The flame retardant used
with the carrier fiber is heat sensitive so compounding the flame
retardant into the carrier fiber is done at a very low heat level
and with low heat history. For a polyphosphate based flame
retardant, concentrated polyphosphate degrades around 285.degree.
C. Preferably the carrier fiber is compound extruded at 280.degree.
C. or lower with no heat history. The extrusion process is given a
low draw ratio of approximately 2-2.5 to prevent crystallinity from
occurring. By creating an amorphous carrier fiber, the carrier
fiber will melt at a lower temperature creating a melted filling
within the pores of the nonwoven material further blocking air and
creating resistance for sound.
[0028] Another advantage of using high melt PET is that the polymer
can come from recycled bottles and the waste from the molded
products can be recycled back into new fibers.
[0029] The invention utilizes a manufacturable or moldable
composite consisting of a blend of composite fibers. The invention
may also utilize at least two layers of moldable nonwoven fabrics.
An extruded layer of blown film is used to make the material
lighter and provide the necessary acoustic qualities of the
material. In addition, a single layer nonwoven can be produced
using the high melt fiber with FR additive and a binder of PETG or
the High melt fiber with a binder of PETG containing the FR
additive.
[0030] The composite material is made from a film such as, but not
limited to low density polyethylene, linear low density
polyethylene, high density polyethylene, polypropylene, polyvinyl
chloride, polyethylene terephalate, polyethylene terephalate
glycol-modified, polyamide, nylon and the like. A polyethylene
glycol-modified (PETG) may be used as a binder fiber. Polylactic
acid (PLA) may also be used in the composite material. Other binder
fibers may be used including Isophthallic modified PET,
polyethylene, and polypropylene. A blowing agent such as an inert
gas of air, nitrogen, carbon dioxide, helium, argon, oxygen or the
like may be used to generate cells within the film. The cells
created provide lighter weight and increased acoustic capability
for the composite material.
[0031] During blending fiber finishes such as Goulston L624
(fluorocarbon) may be applied during blending. Other finishes such
as Lurol 14951 may be blended with L624 to achieve heat and/or fire
retardant characteristics. Anti-stats such as ASY may be added to
improve run ability especially with low humidity conditions.
[0032] The nonwoven material may include polyethylene terephthalate
glycol-modified (PETG) as a binder. When the PETG is melted it
flows uniformly and formed meniscus at the bond points of the high
melt fibers. The level of the PETG percentage controls the
stiffness and the air flow resistance.
[0033] Further the nonwoven may use in addition to or as a
replacement binder Polylactic Acid (PLA) such as fibers made from
Cargill's PLA Ingeo polymer with a melting point of 140.degree. C.
The PLA may or may not be blended with the above PETG fibers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a flow diagram showing one embodiment of
manufacturing a composition in accordance with the present
disclosure.
[0035] FIG. 2 is a cross-sectional view of one embodiment of a
composition in accordance with the present disclosure.
[0036] FIG. 3 is a cross-sectional view of one embodiment of a
composition in accordance with the present disclosure.
[0037] FIG. 4 is a flow diagram illustrating applying finishing
material on the composite for heat exposure in automotive
applications.
[0038] FIG. 5 is a chart showing the Noise absorption results for
samples tested.
[0039] FIG. 6 is a photomicrograph of a sample showing the melted
portions of one of two fibers that decreases pore size to increase
acoustic properties.
DETAILED DESCRIPTION
[0040] In experimental trials, black 6d PET was produced with the
formula which resulted in 2,500 ppm of Polyphosphinate in the
fiber: Clean, PET Bottle flake 92.8%; Americhem 33558-F1 5.0% Black
Pigment 50% in PE 2.2%.
[0041] These fibers were blended with Black PETG 4 denier fibers to
produce a needle-punched nonwoven at a weight of 1,000 grams/
Meter.sup.2. After molding, the product passed the UL 94 test with
a V-0 rating. Fibers can be made from 0.9 denier to 50 denier in
lengths from 25 mm to 180 mm.
[0042] However, incorporating the polyphosphinate into the low melt
fiber such as PETG, Isophthalic modified PET, or polyethylene would
allow extrusion at lower melt temperatures and ensure there is very
little degradation of the polyphosphinate which is susceptible to
significant degradation above 290.degree. C.
[0043] A low melt fiber that incorporates a flame retardant such as
polyphosphinate, organophosphates, phosphonates, antimony trioxide,
or even halogens, would be able to be blended with untreated fibers
such as cotton, wool, flax, jute, or hemp. The low melt fiber could
be blended with all higher melt fibers that have a melt temperature
at least 10.degree. C. (19.degree. F.) higher than the low melt
fiber.
[0044] By blending either high melt fibers with an internal flame
retardant with untreated low melt fibers or by blending untreated
high melt fibers with an internal flame retardant low melt fiber, a
moldable composite suitable for automotive applications requiring
heat stability and excellent flame resistance can be produced.
[0045] Further, blending a high melt fiber with internal flame
retardant with a low melt fiber with an internal flame retardant
produces composites with superior flame resistance.
[0046] Blending a low melt fiber with internal flame resistance
with a natural fiber such as: cotton, wool, flax, jute, or hemp
allows the use of non-inherent flame resistant fibers to be used in
moldable composites. Some of these fibers are naturally resistant
to high heat applications, but cannot be used because they burn
easily. This eliminates the need to apply topical flame retardants
which could cause harmful chemicals to touch the personnel using
these moldable composites.
[0047] Further, nonwoven fabrics can be made by many processes
including but not limited to: Needle Punch, Spun-Lace, Thermal
Bonded, AirLaid and Through Air Bonding.
[0048] Moldable composites can be made in weights from 50 to 2,500
grams per square centimeter. Fibers can be made from 0.7 denier to
100 denier and in lengths from 0.5 to 7 inches for these
applications.
[0049] The high melt fibers can range from 30 to 95% of the blend
while the low melt fibers can range from 5 to 70% of the blend. The
flame retardant additives can range from 0.1 to 7% of the total
fiber by weight. Bi-Component polyester fibers with a low melt
sheath are widely used within the automotive industry for moldable
composites. But, generally, these do not meet the stringent
requirements for the UL-94 flame test. By incorporating the flame
retardant additives shown above in either the core or the sheath of
the fiber, these bi-component fibers could be used in automotive
moldable composites to meet the UL-94 test.
[0050] Blowing agents in film may be utilized to make a bi-layer
(two layers) or tri-layer (tri-lament)with three layers composite
with controlled micro-porosity. In addition various combination may
be used such as 2 film layers with a single composite layer or 2
film layers with 2 composite layers. Various combinations of the
total layers may be used such as placing the film layer between the
two composite layers, or having two film layers outside and
attached to a single composite layer. Layers may be alternated such
as film, composite layer, film, composite layer or composite layer
film, composite layer, film as well as various other combinations
depending on the embodiment. While flame-retardants can easily be
incorporated into the extruded film, it is preferable to
incorporate the flame retardants into the fibers on either side of
the film as the fabric is the first material to be exposed to the
flame.
[0051] Moldable nonwoven fabrics depend on the blending of fibers
with high melt temperatures and fiber of low melt temperatures. The
high melt temperature fibers used are Polyester (PET), PBT,
Polyamide (Nylon 6 or Nylon 6,6), Acrylic, polypropylene,
Polylactic Acid (PLA) and fiberglass. In addition, natural fibers
that do not melt can be used, such as: cotton, wool, flax, jute, or
hemp, and the like.
[0052] Low melt fibers such as: Polyethylene, Isophthalic modified
Polyester, PETG, and co-PLA can be used as the binder fibers to
provide stiffness and durability.
[0053] Generally there is at least at 10.degree. C. (19.degree. F.)
difference in melt temperatures (and usually greater) to allow the
low melt fiber to melt and stick to the high melt fibers. PETG
fibers that are amorphous typically may have a melt temperature of
160-165.degree. C. Eastman Chemical, SK Chemicals, and Artenius
Italia are manufacturers of PETG. Cyclohexane dimethanol (CHDM) can
be added to the polymer backbone in place of ethylene glycol. Since
this building block is much larger (6 additional carbon atoms) than
the ethylene glycol unit it replaces, it does not fit in with the
neighboring chains the way an ethylene glycol unit would. This
molecular structure interferes with crystallization and lowers the
polymer's melting temperature. In general, such PET is known as
PETG or PET-G (Polyethylene terephthalate glycol-modified). The
most common Eastman PETG types used during the experiments were:
6763; 14471; and GN-071.
[0054] Nonwoven Network, LLC pioneered a Tri-layer product known as
Raptor.TM. that contains a 500 gsm (grams per square meter)
polyester absorber layer, and 150 gsm PP film layer acting as a
barrier layer, and a 375 gsm polyester absorber layer. This product
provides superior sound attenuation qualities and also has an
impervious layer that prevents water from penetrating to the metal
frame of the vehicle.
[0055] Further, Nonwoven Network LLC has developed a new concept in
acoustic noise reduction from the wheel wells, especially in Sport
Utility Vehicles. Raptor.TM. is a tri-laminate composite that
incorporates an absorber layer-barrier layer-absorber layer to
dramatically reduce the noise in the cabin with vehicles with large
tires and aggressive treads. The product is in full production in a
recently launched vehicle and has received outstanding reviews for
sound and durability.
[0056] The Tri-Layer Raptor.TM. product has the best acoustics for
a 1,015 gsm product, however there is a need to improve its
performance while keeping the weight at the same level.
[0057] The invention utilizes a low melt fiber made from a
co-polyester where cyclohexane dimethanol (CHDM) has been
substituted for some of the ethylene glycol (EG) normally
polymerized with Purified Terephthalic Acid to produce Polyester
(PET). The result is a polymer called PETG. The melting point of
the polymer can be adjusted from 110.degree. C. to 170.degree. C.
by adjusting the ratio of CHDM to EG.
[0058] The PETG will be blended with Standard PET fiber that has
been heat set to 190.degree. C.
[0059] Fibers made from Polylactic Acid (PLA) such as fibers made
from Cargill's PLA Ingeo polymer the have been drawn and fully
crystallized with a melting point of 140.degree. C. and above are
blended with Polyester (PET) fibers that have been heat set at
170.degree. C. or above.
[0060] The plastics industry has used Blowing Agents to expand the
plastic films and injection molded parts by injecting inert gasses
such as N.sub.2 (Nitrogen) or CO.sub.2 (Carbon Dioxide). The first
known use was in 1846 when Hancock received a patent to make
synthetic sponges with rubber. Other blowing agents such as Sodium
Bi-Carbonate (Commonly known as Baking Powder) have been used in
bakery products (cakes) and plastics. Ethylene Carbonate decomposes
with heat to produce CO.sub.2 Ammonium Nitrate decomposes with heat
to produce N.sub.2.
[0061] Examples of companies that make Blowing agents for plastic
extrusion include Techmer, Clariant, Reedy, Kibbechem, Wells, and
Beryl for example.
[0062] It is also possible to inject inert gasses directly into the
extruder as shown by Linde Industrial gasses such as Nitrogen,
Argon, Helium, and Carbon Dioxide and the like.
[0063] Further blending in a blowing agent at a rate of 0.1 to 3.0%
will provide inert gasses to allow a producer to make the film
lighter in weight at the same thickness. Alternatively, by
maintaining the same film weight, the thickness increases. The
additional thickness can increase the flexural modulus, thus
producing a stiffer part.
[0064] By combining the blown film with 1 or 2 fabric layers, a
thermo-formable composite can be made. The blown film is protected
by the fabrics. Since the fabrics contain a high percentage of low
melt formable fibers, a very stiff and durable composite can be
formed.
[0065] The following are examples given to illustrate the benefits
of the present invention. These examples are in no means meant to
limit the invention to these particular embodiments.
EXAMPLE 1
[0066] In the first example, GA24, the following was used:
[0067] Layer 1: 200 gsm 70% Type P110 6d Black Polyester/30% Black
4 denier PETG.
[0068] Layer 2: 150 gsm Blown HDPE film with 1.0% Techmer Blowing
agent.
[0069] Layer 3: 650 gsm 70% Type P110 6d Black Polyester/30% Black
4 denier PETG
[0070] Total weight 1,000 gsm
[0071] The Extrusion temperature was 210.degree. C. to achieve full
blowing potential. The products were molded using a 210.degree. C.
oven to preheat the composite assuring that the 165.degree. C. melt
point of the PETG fiber was achieved.
[0072] The result was a very stiff molded part with excellent
flexural modulus.
[0073] The molded composite was tested for RAYLS and found to be
very high with little porosity, but with some porosity. It was then
subjected to Acoustic testing with excellent results.
[0074] The molded composite withstood long term heat and
environmental aging.
EXAMPLE 2
[0075] In the second example, GA25 the following was used:
[0076] Layer 1: 200 gsm 70% Type P110 6d Black Polyester/30% Black
4 denier PETG
[0077] Layer 2: 100 gsm Blown HDPE film with 1.0% Techmer Blowing
agent
[0078] Layer 3: 700 gsm 70% Type P110 6d Black Polyester/30% Black
4 denier PETG
[0079] Total weight 1,000 gsm.
[0080] The Extrusion temperature was 210.degree. C. to achieve full
blowing potential. The products were molded using a 210.degree. C.
oven to preheat the composite assuring that the 165.degree. C. melt
point of the PETG fiber was achieved.
[0081] The result was a very stiff molded part with excellent
flexural modulus.
[0082] The molded composite was tested for RAYLS and found to be
very high with little porosity, but better than GA24. It was then
subjected to Acoustic testing with excellent results.
[0083] The molded composite withstood long term heat and
environmental aging.
[0084] It was determined that the composites could be made with
other blends of Polyester, Polypropylene, Nylon, Cotton, or other
types of fibers. Other binder fibers could also be used.
[0085] The extruded film could be made from any thermoplastic resin
such as LDPE, LLDPE, HDPE, Polypropylene, PVC, PET, Polyamide
(Nylon), EVA and the like.
[0086] Adverting to the drawings, FIG. 1 illustrates a flow diagram
of one embodiment of extruding the bi and/or tri layer composite
composition. As shown, extruder 10 may be a standard single screw
or twin screw extruder depending on the embodiment. A resin 14 is
place in the extruder's hopper with blowing agent 16. The resin 14
may be among other things any polyolefin such as but not limited to
HDPE, LLDPE, LDPE, and the like. Resin 14 may also be any of the
polymers mentioned in specification and claims. Blowing agent 16
may be a chemical blowing agent as previous described and/or a gas
injected blowing agent depending on the embodiment.
[0087] The extruder 10 has a mixing screw 12 that melts the resin
pellets and mixes the blowing agent to generate microscopic voids.
The voids are preferably open cell holes for use in acoustic
impedance as described herein. An extrusion die 18 sets the film
thickness of the polymer. And creates a film 20 with the
microscopic voids or holes.
[0088] Depending on the implementation of either a bi-layer or
tri-layer composite material, a fabric (non-woven) layer 22 is
released from roll 23 and may or may not be stretched or worked,
depending on the embodiment, for nonwoven fabric 27 to be attached
to film 20 by nip rolls 28.
[0089] In a tri-layer composite implementation, another fabric
(non-woven) layer 24 is released from roll 25. Again the nonwoven
layer may or may not be stretched or worked, depending on the
embodiment, for nonwoven fabric 26 to be attached to film 20 by nip
rolls 28. Nip rolls 28 may or may not be chilled or heated
depending on the embodiment. Nip rolls 28 also use mechanical
pressure to squeeze the layers together. Nonwoven fabric may be
made of any compositions discussed in this specification. PETG,
Polyethylene, isophthallic modified PET, and/or PLA may also be
used as binders in the non-woven fabric. Examples of non-woven
materials include for example, and are not limited to, cellulosic,
keratin, wool, cotton, polyesters, fabric, polylactic acids,
nylons, rayon, polypropylene, and any combination thereof. In
either a bi-layer or tri-layer composite the grams per square meter
(gsm) of each layer may be controlled by nips 28 and/rollers 23,
25, and/or the line speed of the extrusion line and/or the amount
of blowing agent 16. In a tri-layer composite embodiment 29, for
example layer 1 of a nonwoven material may be 1-200 gsm, layer 2 of
a blown film may be 1150 gsm, and layer 3 of a nonwoven fabric may
be 650 gsm, for example.
[0090] FIG. 2 illustrates a moldable end product 200 of the
extrusion process shown in FIG. 1 using a tri-layer composite end
product. In FIG. 2, a layer of moldable polyester 210 having a 200
gsm is used. The second layer 220 is the blown film layer and in
this example made of high density polyethylene (HDPE) with a 150
gsm. The third layer is a nonwoven moldable polyester 230 having a
650 gsm. The microscopic holes or cells in the blown film 220
assist with the acoustic impedance quality of the moldable material
200. This composite 200 now may be molded in any shape for
automotive or other uses to assist in sound quality and acoustic
impedance.
[0091] FIG. 3 illustrates a moldable end product 300 of the
extrusion process shown in FIG. 1 using a bi-layer composite end
product. In FIG. 3, a layer of moldable fabric 310 having a 650 gsm
is used. The second layer 320 is the blown film layer and in this
example made of high density polyethylene (HDPE) with a 100 gsm. No
third layer is used in this embodiment. The microscopic holes or
cells in the blown film 320 assist with the acoustic impedance
quality of the moldable material 300. This composite 300 now may be
molded in any shape for automotive or other uses to assist in sound
quality and acoustic impedance.
[0092] Additional materials may also be applied to any fibrous
element. For example, the PTEG or PLA fibers or any of the
non-woven materials or blown film described above may be treated
with a performance enhancing finish, either during fiber formation
or fiber blending. The finish types may vary depending on the
embodiments. In some embodiments, the finish is comprised of a
fluorocarbon, such as the CF fluorocarbon sold by Goulston
Technologies as FC-L624. This enhances among other things the
durability and moisture resistance of the moldable fabric. In other
embodiments, the finish is comprised of an inorganic phosphate
salt, such as that sold by Goulston Technologies as L-14951. This
enhances additive also enhances the heat resistance and flame
retardant and/or durability of the moldable fabric. In either
instance, the performance enhancing finish preferably does not
exceed 0.05% to 1.0% of the fiber weight. An alternate finish may
also be comprised of a combination of a fluorocarbon and an
inorganic phosphate salt to achieve fire retardant characteristics.
Preferably, this alternate finish does not exceed 0.05% to 2.0% of
the fiber weight. An anti-static element, such as ASY, may also be
added to improve run ability, especially when the moldable fiber is
manufactured within a low humidity environment.
[0093] FIG. 4 illustrates a flow diagram for a non-woven fabric.
Shown as an example, PET fiber 400, with PETG fiber 410 and PLA
fiber 420 is blended in a blending machine 430. A finishing
application 450 is accomplished adding additives for example those
shown, but not limited to, additives in block 440. A fabric
formation 46 is made that may be further molded as a product as
shown in molding fabric 470 or utilized as a nonwoven fabric in the
extrusion process explained in FIG. 1.
[0094] FIG. 5 illustrates a graph showing significantly reduced
noise using the tested fabric. As shown 700 gsm and 1000 gsm
samples had superior noise absorption qualities.
[0095] FIG. 6 is a photomicrograph showing the decreased pore size
in a non-woven material by the melting of one of the two fibers.
Decreased pore size is attributable to the increased acoustic
properties (noise absorption) of the fabric.
[0096] Although the invention herein has been described with
reference to particular embodiments, it is to be understood that
these embodiments are merely illustrative of the principles and
applications of the present invention. It is therefore to be
understood that numerous modifications may be made to the
illustrative embodiments and that other arrangements may be devised
without departing from the spirit and scope of the present
invention as defined by the appended claims.
* * * * *